Background: To determine whether human T-lymphotropic virus type II (HTLV-II) infection is associated with an increased incidence of bacterial infections, we prospectively observed cohorts of HTLV-I- and HTLV-II-infected and seronegative subjects in 5 US cities.
Methods: Of 1340 present and former blood donors examined at enrollment, 1213 (90.5%) were re-examined after approximately 2 years, including 136 HTLV-I- and 337 HTLV-II-seropositive subjects and 740 demographically stratified HTLV-seronegative subjects. All subjects were seronegative for human immunodeficiency virus. Odds ratios (ORs) for incident disease outcomes were adjusted for covariates, including age, sex, race or ethnicity, education, and, if significantly associated with the outcome, blood center, donation type, income, smoking, alcohol intake, and injected drug use.
Results: Compared with seronegative status, HTLV-II infection was associated with an increased incidence of bronchitis (OR, 1.81; 95% confidence interval [CI], 1.20-2.75), bladder and/or kidney infection (OR, 1.94; 95% CI, 1.26-2.98), oral herpes infection (OR, 9.54; 95% CI, 3.33-27.32), and a borderline increased incidence of pneumonia (OR, 2.09; 95% CI, 0.92-4.76); HTLV-I infection was associated with an increased incidence of bladder and/or kidney infection (OR, 2.79; 95% CI, 1.63-4.79). One incident case of HTLV-I-positive adult T-cell leukemia was observed (incidence, 348 per 100,000 HTLV-I person-years), and 1 case of HTLV-II-positive tropical spastic paraparesis-HTLV-associated myelopathy was diagnosed (incidence, 140 per 100,000 HTLV-II person-years).
Conclusions: These data support an increased incidence of infectious diseases among otherwise healthy HTLV-II- and HTLV-I-infected subjects. They are also consistent with the lymphoproliferative effects of HTLV-I, and with neuropathic effects of HTLV-I and HTLV-II.